Surge tanks for refrigeration systems



Nov. 17, 1970 D. EVANS SURGE TANKS FOR REFRIGERATION SYSTEMS Filed May 27, 1969 2 Sheets-Sheet 1 iii IHHHHIW.

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D. L. EVAN S' SURGE TANKS FOR REFRIGERATION SYSTEMS Nov. 17, 1970 2 Sheets-Sheet 2 Filed May 27, 1969 INVENTOR: DARL L. EVANS ATTYS.

United States Patent 3,540,230 SURGE TANKS FOR REFRIGERATION SYSTEMS Darl L. Evans, Bloomsburg, Pa., assignor to Girton Manufacturing Company, Inc., Millville, Pa., a corporation of Pennsylvania Filed May 27, 1969, Ser. No. 828,212 Int. Cl. F25b 43/02 US. Cl. 62-471 8 Claims ABSTRACT OF THE DISCLOSURE A surge tank for refrigeration systems comprising an upper surge chamber and an underlying smaller recirculating chamber in fluid communication with the surge chamber. Liquid refrigerant discharged from the evaporator to the surge tank is accumulated in the recirculating chamber and the lower portion of the surge chamber and is recirculated to the evaporator together with high pres sure refrigerant discharged from an injector pump mounted in the recirculating cham ber. Baflles are provided in the surge chamber of the tank and arranged with respect to the gaseous refrigerant outlet therefrom so that lubricating oil entrained in the refrigerant discharged from the evaporator to the surge tank and collecting on the surface of the liquid refrigerant in the surge tank is caused to be drawn off with the gaseous refrigerant and recirculated to the refrigerant compressor.

The present invention relates to refrigeration apparatus, and more particularly to improvements in surge tanks for refrigeration systems of the type wherein unevaporated liquid refrigerant discharged from the evaporator is accumulated in the surge tank and recirculated to the evaporator together with the high pressure refrigerant from the compressor. The invention is an improvement upon the refrigeration system disclosed in my earlier US. Patent 2,859,596 issued Nov. 11, 1958.

Another object of the present invention is to provide an improved surge tank for refrigeration systems which is constructed and arranged to substantially reduce the overall height and space requirement for housing the refrigeration system in which employed.

Another object of the invention is to provide a surge tank construction of the type described wherein the head of liquid refrigerant accumulated therein is of substantially less height than heretofore with a consequent proportionate reduction in the total charge of refrigerant required for efficient operation of the refrigeration systern.

Another object of the invention is to provide a surge tank wherein provision is made for the continuous recirculation tothe compressor of lubricating oil entrained in the refrigerant returned to the surge tank from the evaporator.

Another object of the invention is to provide a surge tank construction wherein an overcharge of refrigerant in the system will be visably indicated to persons observing operation of the system.

A further object of the invention is to provide a surge tank of the type described having a novel construction and arrangement which effectively minimizes or eliminates the formation of a vortex or vortices in the liquid refrigerant as it is drawn from the surge tank and entrained with the high pressure refrigerant supplied to the evaporator thereby providing for more eflicient operatiton of the refrigeration system.

These and other objects of the invention and the various features and details thereof are hereinafter more fully set forth and described with reference to the accompanying drawings, in which:

3,540,230 Patented Nov. 17, 1970 FIG. 1 is a schematic view diagrammatically illustrating a refrigeration system embodying a surge tank constructed and arranged according to the present invention.

FIG. 2 is an enlarged sectional view on line 22, FIG. 1, and

FIG. 3 is an enlarged sectional view on lines 33, FIG. 1.

Referring to FIG. 1 of the drawings, the refrigeration system comprises a conventional refrigerant compressor 1 operable to discharge compressed volatile refrigerant through a pipe 2 to a condenser 3 and thence through a pipe 4 to a receiver 5. From the receiver 5 the refrigerant flows through a pipe 6 to a heat exchanger 7 in which the high pressure refrigerant is cooled by the low pressure refrigerant returned from the evaporator to the compressor 1 as hereinafter described. From the heat exchanger 7 the cooled high pressure refrigerant flows through a pipe 8 to and through a suitable filter 9 and thence through a pipe 10 to the inlet 11 of an injector or pump 12.

The pump 12 has a refrigerant pressure and flow control orifice 13 located in advance of a nozzle 14 from which the precooled high pressure refrigerant is discharged through a pipe 15 into an evaporator 16. The evaporated gaseous refrigerant is discharged from the up per end of the evaporator 16 through one or more pipes 17 into a surge tank T from which the spent refrigerant gas is drawn by suction into and through a pipe 18, the heat exchanger 7 and a pipe 19 to the suction inlet of the compressor 1.

The present invention is particularly concerned with the construction and arrangement of the aforesaid surge tank T. Referring to the drawings, and particularly FIGS. 2 and 3 thereof, the surge tank T is an elongated horizontally disposed structure comprising an upper surge chamber 20 and an underlying refrigerant recirculating chamber 21. The surge chamber 20 is of substantially greater capacity than the chamber 21 and the two chambers are in fluid communication with each other through ports 22 disposed in substantially spaced relation adjacent opposite ends of the chamber 21.

According to the present invention, the refrigerant injector or pump 12 is mounted in a tubular sleeve 23 that extends through the recirculating chamber 21 of the surge tank T. In the illustrated embodiment of the invention the sleeve 23 extends transversely through the chamber 21 midway between the ends thereof and is fixedly secured in position, for example, by welding, as indicated at 24. The high pressure refrigerant feed pipe 10 is connected to the inlet 11 of the refrigerant pump 12 by means of a fitting 25 threaded on the adjacent end of the sleeve 23, as shown in FIG. 2, and the opposite end of the sleeve 23 is similarly connected by means of a threaded fitting 26 to the refrigerant pipe 15 which leads to the evaporator 16.

The portion of the sleeve 23 that is disposed within the recirculating chamber 21 is provided with a plurality of circumferentially spaced ports 27 arranged in circumscribing relation to the discharge end of the pump nozzle 14. In operation of the refrigeration system the refrigerant which is discharged from the evaporator 16 into the surge tank T includes a certain amount of entrained unevaporated liquid refrigerant that accumulates in the recirculating chamber 21, and the precooled high pressure refrigerant discharged from the pump nozzle 14 operates to draw or aspirate this accumulated unevaporated refrigerant through the ports 27 into the sleeve 23 and recirculates the same, together with the high pressure refrigerant, through the sleeve 23 and pipe 15 to the evaporator 16.

In accordance with the illustrated embodiment of the invention, the pipes 17, through which refrigerant "ice is discharged from the evaporator 16 to the surge tank T, are connected, respectively, to the opposite ends of the surge chamber through ports 28 provided in the end walls thereof, for example, as shown in FIGS. 2 and 3 of the drawings. The suction pipe 18 for evaporated refrigerant is connected to the surge chamber 20 of the tank T at a port 29 provided in a side wall of of the tank intermediate the ends thereof and located at a predetermined height above the bottom or floor of the surge chamber 20.

A pair of baflies 30, are mounted transversely or crosswise of the surge chamber 20 in spaced parallel relation to each other and disposed, respectively, at opposite sides of the suction port 29 and between the latter and the adjacent port 22 that communicates with the underlying recirculating chamber 21 as shown in FIG. 3 of the drawings. The baffles 30, 30 do not extend the full height of the surge chamber 20 and have their upper edges spaced below the top of the chamber 20 to provide for free flow of gaseous refrigerant from the inlet ports 28 over the baffles 30, 30 to the suction outlet port 29'.

Provided in each baffle 30' is a small port or opening 31 that is positioned at a predetermined height above the bottom or floor of the chamber 20 and substantially in the plane of the bottom of the cricumference of the suction outlet port 29, as shown in FIGS. 2 and 3. In normal operation, the refrigeration system is charged with refrigerant, such as Freon, in an amount so that the unevaporated liquid refrigerant discharged from the evaporator 16 to the surge tank T will entirely fill the recirculating chamber 21 and the lower portion of the surge chamber 20 to the level of the ports 31 in the baflles 30 and also flow through said ports 31 and the bottom of the suction outlet port 29.

The refrigerant discharged from the evaporator 16 into the surge chamber 20 contains an amount of entrained oil for lubricating the compressor 1. Upon entering the surge chamber the entrained lubricating oil will separate from the refrigerant and collect on the surface of the pool of unevaporated liquid refrigerant in the surge chamber 20 flowing through the ports 31 in the baffles 30 to the suction port 29. Thus the lubricating oil will be withdrawn from the surge chamber 20 along with the spent gaseous refrigerant through the suction port 29, pipe 18, heat exchanger 7 and pipe 19 to the suction intake of the compressor 1. By this construction the lubricating oil entrained in the refrigerant is continuously returned to and recirculated through the compressor 1 to lubricate the latter.

In the event that the system becomes overcharged with refrigerant the level of the unevaporated liquid refrigerant in the surge chamber 20 will rise to a height above the ports 31 in the baffles 30 with the result that liquid refrigerant will be withdrawn from the chamber 20 into the suction pipe 18 exteriorly adjacent the surge tank T and provide a visual indication that the system is overcharged. The operator can then return the system to normal operating conditions by bleeding high pres sure refrigerant from the system in the amount required to eliminate the occurrence of frost or icing on the pipe 18 thus indicating that the level of the unevaporated refrigerant in the surge chamber 20 has been lowered to the normal level of the ports 31 in the baffles 30.

The elongated horizontal construction and arrangement of the surge tank of the present invention substantially reduces the overall height of the refrigeration system as compared to systems employing other types of surge tanks such as, for example, the large vertically extending tank shown and described in my earlier US. patent previously identified. The present construction also provides a lower head of liquid refrigerant and a proportionately smaller total charge of refrigerant in the system than heretofore necessary.

The novel construction and arrangement of the surge tank further provides for the continuous recirculation to the compressor of lubricating oil entrained in the refrigerant returned to the surge tank from the evaporator, and also provides a visible indication in the case of an overcharge of refrigerant in the system so that excess refrigerant can be removed and the system returned to normal operating conditions. The arrangement of the inlet ports 22 to the recirculating chamber 21 in substantially laterally spaced relation at opposite sides of the pump sleeve 23 as shown in FIG. 3 of the drawings effectively minimizes or eliminates formation of a vortex or vortices in the refrigerant as it flows through the ports 27 into the refrigerant pump sleeve 23 for recirculation to the evaporator 16, thereby providing more efiicient operation of the refrigeration system.

While a particular embodiment of the invention has been illustrated and described it is not intended to limit the invention to such disclosure and changes and modifications may be made and incorporated within the scope of the claims.

I claim:

1. A surge tank for compressor-evaporator type refrigeration systems comprising a casing having top, bottom and side walls defining a horizontally extending surge chamber of predetermined capacity, means defining at least one inlet port in a side wall of the surge chamber for admitting spent refrigerant thereto from the evaporator, means defining a suction outlet port in a side wall of the surge chamber for exhausting gaseous refrigerant therefrom, said outlet port being disposed in horizontally spaced relation from said inlet port and spaced a predetermined distance above the bottom wall of the surge chamber, a vertical baffle subdividing the surge chamber between the said at least one inlet port and outlet port and extending upwardly from the bottom wall of the chamber a predetermined distance terminating below the top wall thereof, said baffle having a port therethrough spaced above the bottom wall of the surge chamber at least the same distance as said outlet port, and means defining a liquid refrigerant recirculating chamber of substantially smaller capacity than the surge chamber underlying the latter and having fluid communication therewith through at least one opening in the bottom wall of the surge chamber.

2. A surge tank as claimed in claim 1 wherein the opening in the bottom wall of the surge chamber providing fluid communication between the latter and the recirculating chamber is located at the opposite side of the baffle from the suction outlet port.

3. A surge tank as claimed in claim 1 wherein a high pressure refrigerant injector pump is mounted in the recirculating chamber and there is means providing fluid communication from the recirculating chamber to said injector pump whereby the latter operates to draw accumulated liquid refrigerant from said chamber and discharge same with high pressure refrigerant to the evaporator.

4. A surge tank as claimed in claim 3 wherein the fluid inlet to the injector pump from the recirculating chamber is disposed in horizontally spaced relation from the fluid inlet from the surge chamber to said recirculating cham- 5. A surge tank as claimed in claim 1 wherein means defines a pair of inlet ports to the surge chamber disposed in substantially spaced apart relation at respectively opposite sides of the suction outlet port in said chamber, and a pair of baflies is provided in said surge chamber with one balfle of said pair subdividing the surge chamber between said outlet port and one of said inlet ports and the other baffle subdividing the chamber between said outlet port and the other of said inlet ports.

6. A surge tank as claimed in claim 5 wherein the recirculating chamber is in fluid communication with the surge chamber through a pair of openings in the bottom wall thereof, said openings being horizontally spaced from each other and located respectively at opposite sides of the baflies from the suction outlet port.

7. A surge tank as claimed in claim 6 wherein a high pressure refrigerant injector pump is mounted in the recirculating chamber and the fluid inlet thereto from the said chamber is disposed in horizontally spaced relation from and between the fluid inlet openings to the recirculating chamber from the surge chamber.

8. A surge tank as claimed in claim 5 wherein a high pressure refrigerant injector pump is mounted in the recirculating chamber and there is means providing fluid communication from the recirculating chamber to said injector pump whereby the latter operates to draw accumulated liquid refrigerant from said chamber and discharge same with high pressure refrigerant to the evaporator.

References Cited UNITED STATES PATENTS 2,117,506 5/1938 Reinhardt 625 12 2,156,426 5/1939 Brown 62512 2,691,873 10/1954 Skoli 62503 10 MEYER PERLIN, Primary Examiner US. Cl. X.R. 62503, 512 

